This invention relates generally to a device for storing green tires during a pre-curing wait cycle.
In the manufacture of a tire, its various components, including reinforcing components embedded in a matrix of unvulcanized rubber or other unvulcanized rubberlike material, are assembled on a building form. The tire at this stage of the manufacturing process is commonly called a green tire. After being built, a green tire is transported to a doping/curing area whereat it is doped. Thereafter, the green tire is subjected to a shaping and vulcanizing press and shaped into its final form. There is almost always a waiting period between the doping of the green tire and its subsequent curing. This time period can be referred to as the pre-curing wait cycle and can extend anywhere from a few hours to several days.
During the pre-curing wait cycle, a green tire is usually stored on a holding device. Of particular relevance to the present invention is a green tire holding device having a plurality of horizontal arms (e.g., eight) each on which a number of green tires (e.g., three) are hung. The horizontal arms can have a crosssectional shape compatible with this hanging. For example, the arm can have a half-moon shape to form a sling for the green tires.
In its vertical hanging position, a green tire has a tendency to sag or droop under its own weight, due to gravitational forces on the unsupported portions of the green tire, and become distorted. Specifically, because only an upper portion of the green tire rests on the horizontal arm, this portion is constantly subjected to the gravitational pull of the lower portions of the green tire.
The present invention provides a green tire storage device that counters the constant gravitational forces for a green tire during the pre-curing wait cycle for that tire.
More particularly, the present invention provides a green tire holding device comprising a frame, a rod extending horizontally from the frame, and a bladder mounted on the rod. The bladder is inflatable from a deflated shape to an inflated shape so that it can contact a substantial portion of an inner circumference of the green tire to support the green tire during a pre-curing wait cycle. Preferably, the inflated size of the bladder can be varied so that the green tire storage device can accommodate green tires of different sizes without any structural modifications.
The green tire holding device can comprise a plurality of rods, a plurality of bladders, and/or a plurality of bladders on each rod. The frame can include an inlet connection valve and a conduit system can connect the inlet connection valve to each of the bladders. The conduit system can be such that a plurality of the bladders are inflated at substantially the same time. Additionally or alternatively, the conduit system can be such that certain bladders can be deflated independently of other bladders. For example, if the green tire holding devices includes a plurality of rods, and each rod includes a plurality of bladders, an outlet valve could be provided for deflating the bladders mounted on one rod independent of the bladders mounted on the other rods.
In a method of making a tire according to the present invention, a green tire is made and then placed on the rod of the holding device with the bladder being in a deflated condition. The bladder is inflated during the pre-curing wait cycle. When the time arrives to cure the green tire, the bladder is deflated, the green tire is removed from the rod, and the tire is cured. The green tire holding device can be transported to another location after the tire is placed thereon. If this transportation is to a doping/curing area, the tire(s) can be removed, doped, and then returned to the rod prior to inflating the bladder(s).
The present invention provides these and other features hereinafter fully described and particularly pointed out in the claims. The following description and drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention can be employed.